The EVK1100 power system generates several voltages. The voltage supplies are sequenced such that the highest voltages activate first.
Block Diagram
The power system of EVK1100 consists of three regulators. A 2.1mm DC jack cable or the USB power input can be used to connect power to the system. A power switch is included to switch between jack power input and USB power input. A high current diode ensures that correct polarity is applied.
Signals
The three regulators have the following features:
-
The 5V switched regulator is the master regulator delivering power to all other power regulators. The reason for this is the allowed input voltage range for the remaining regulators.
-
The 3.3V linear regulator delivers power to all peripherals on the board. The EVK1100 is a 3.3V system.
-
The 1.8V internal regulator delivers power to CPU core.
Power Sequencing
Power is implemented such that the 5V enables the 3V regulator and the 3V regulator enables the 1.8V regulator. The power LED on the EVK1100 is turned on by the 3V regulator.
Current Capabilities of the Power Converters
The power supplies are limited by the internals of the converter and the inductors used for the switched power supplies. Since the 5V converter delivers power to the other converters, the maximum current for this converter is a function of the other converters. The same applies for the 3.3V converter.
The maximum current that can be sinked from the different voltage converters listed below. The listed current is the current that on-board peripherals and user expansion boards can sink together.
| Voltage | Recommended maximum current |
|---|---|
| 5.0V | 1 A |
| 3.3V | 0.8 A |
| 1.8V | Internally Limited |